1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1983, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #ifndef lint
33 #if 0
34 static char sccsid[] = "@(#)table.c 8.1 (Berkeley) 6/4/93";
35 #endif
36 #endif /* not lint */
37
38 /*
39 * Routines to handle insertion, deletion, etc on the table
40 * of requests kept by the daemon. Nothing fancy here, linear
41 * search on a double-linked list. A time is kept with each
42 * entry so that overly old invitations can be eliminated.
43 *
44 * Consider this a mis-guided attempt at modularity
45 */
46 #include <sys/param.h>
47 #include <sys/time.h>
48 #include <sys/socket.h>
49 #include <netinet/in.h>
50 #include <protocols/talkd.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <syslog.h>
55 #include <unistd.h>
56
57 #include "extern.h"
58
59 #define MAX_ID 16000 /* << 2^15 so I don't have sign troubles */
60
61 #define NIL ((TABLE_ENTRY *)0)
62
63 static struct timespec ts;
64
65 typedef struct table_entry TABLE_ENTRY;
66
67 struct table_entry {
68 CTL_MSG request;
69 long time;
70 TABLE_ENTRY *next;
71 TABLE_ENTRY *last;
72 };
73
74 static void delete(TABLE_ENTRY *);
75
76 static TABLE_ENTRY *table = NIL;
77
78 /*
79 * Look in the table for an invitation that matches the current
80 * request looking for an invitation
81 */
82 CTL_MSG *
find_match(CTL_MSG * request)83 find_match(CTL_MSG *request)
84 {
85 TABLE_ENTRY *ptr, *next;
86 time_t current_time;
87
88 clock_gettime(CLOCK_MONOTONIC_FAST, &ts);
89 current_time = ts.tv_sec;
90 if (debug)
91 print_request("find_match", request);
92 for (ptr = table; ptr != NIL; ptr = next) {
93 next = ptr->next;
94 if ((ptr->time - current_time) > MAX_LIFE) {
95 /* the entry is too old */
96 if (debug)
97 print_request("deleting expired entry",
98 &ptr->request);
99 delete(ptr);
100 continue;
101 }
102 if (debug)
103 print_request("", &ptr->request);
104 if (strcmp(request->l_name, ptr->request.r_name) == 0 &&
105 strcmp(request->r_name, ptr->request.l_name) == 0 &&
106 ptr->request.type == LEAVE_INVITE)
107 return (&ptr->request);
108 }
109 return ((CTL_MSG *)0);
110 }
111
112 /*
113 * Look for an identical request, as opposed to a complimentary
114 * one as find_match does
115 */
116 CTL_MSG *
find_request(CTL_MSG * request)117 find_request(CTL_MSG *request)
118 {
119 TABLE_ENTRY *ptr, *next;
120 time_t current_time;
121
122 clock_gettime(CLOCK_MONOTONIC_FAST, &ts);
123 current_time = ts.tv_sec;
124 /*
125 * See if this is a repeated message, and check for
126 * out of date entries in the table while we are it.
127 */
128 if (debug)
129 print_request("find_request", request);
130 for (ptr = table; ptr != NIL; ptr = next) {
131 next = ptr->next;
132 if ((ptr->time - current_time) > MAX_LIFE) {
133 /* the entry is too old */
134 if (debug)
135 print_request("deleting expired entry",
136 &ptr->request);
137 delete(ptr);
138 continue;
139 }
140 if (debug)
141 print_request("", &ptr->request);
142 if (strcmp(request->r_name, ptr->request.r_name) == 0 &&
143 strcmp(request->l_name, ptr->request.l_name) == 0 &&
144 request->type == ptr->request.type &&
145 request->pid == ptr->request.pid) {
146 /* update the time if we 'touch' it */
147 ptr->time = current_time;
148 return (&ptr->request);
149 }
150 }
151 return ((CTL_MSG *)0);
152 }
153
154 void
insert_table(CTL_MSG * request,CTL_RESPONSE * response)155 insert_table(CTL_MSG *request, CTL_RESPONSE *response)
156 {
157 TABLE_ENTRY *ptr;
158 time_t current_time;
159
160 clock_gettime(CLOCK_MONOTONIC_FAST, &ts);
161 current_time = ts.tv_sec;
162 request->id_num = new_id();
163 response->id_num = htonl(request->id_num);
164 /* insert a new entry into the top of the list */
165 ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY));
166 if (ptr == NIL) {
167 syslog(LOG_ERR, "insert_table: Out of memory");
168 _exit(1);
169 }
170 ptr->time = current_time;
171 ptr->request = *request;
172 ptr->next = table;
173 if (ptr->next != NIL)
174 ptr->next->last = ptr;
175 ptr->last = NIL;
176 table = ptr;
177 }
178
179 /*
180 * Generate a unique non-zero sequence number
181 */
182 int
new_id(void)183 new_id(void)
184 {
185 static int current_id = 0;
186
187 current_id = (current_id + 1) % MAX_ID;
188 /* 0 is reserved, helps to pick up bugs */
189 if (current_id == 0)
190 current_id = 1;
191 return (current_id);
192 }
193
194 /*
195 * Delete the invitation with id 'id_num'
196 */
197 int
delete_invite(u_int32_t id_num)198 delete_invite(u_int32_t id_num)
199 {
200 TABLE_ENTRY *ptr;
201
202 if (debug)
203 syslog(LOG_DEBUG, "delete_invite(%d)", id_num);
204 for (ptr = table; ptr != NIL; ptr = ptr->next) {
205 if (ptr->request.id_num == id_num)
206 break;
207 if (debug)
208 print_request("", &ptr->request);
209 }
210 if (ptr != NIL) {
211 delete(ptr);
212 return (SUCCESS);
213 }
214 return (NOT_HERE);
215 }
216
217 /*
218 * Classic delete from a double-linked list
219 */
220 static void
delete(TABLE_ENTRY * ptr)221 delete(TABLE_ENTRY *ptr)
222 {
223
224 if (debug)
225 print_request("delete", &ptr->request);
226 if (table == ptr)
227 table = ptr->next;
228 else if (ptr->last != NIL)
229 ptr->last->next = ptr->next;
230 if (ptr->next != NIL)
231 ptr->next->last = ptr->last;
232 free((char *)ptr);
233 }
234